bfd_close_all_done bug and bfd_last_cache

bfd_close ought to always call iovec->bclose so that cache_bclose is
called.  If not, bfd_last_cache will be left pointing at freed memory.
This bug was found by oss-fuzz with the trigger being an old bug in
the ia64-vms support.  Given a file of the "wrong" size,
elf64_vms_close_and_cleanup attempted to extend it, leading to an
error since the file was opened read-only by nm.  nm bad_file bad_file
then hit the use-after-free when opening the second file.

commit 8219cab3f8 fixed multiple bugs of this type in bfd_close and
bfd_close_all_done, but didn't go quite far enough.

	* elf64-ia64-vms.c (elf64_vms_close_and_cleanup): Don't
	attempt to extend read-only files.
	* opncls.c (bfd_close_all_done): Always call _close_and_cleanup.

An old bug in the ia64-vms support can be used to tickle another bug
in bfd_close_all_done.  If _close_and_cleanup returns an error,